Plugs and sockets are typically used in an electrical system for providing electrical connectivity between devices. Connecting an incompatible plug to an incorrect socket may lead to adverse consequences such as circuit malfunction or overloading.
For example, in an electrical system involving the use of a plug-in relay between a controlling circuit and a controlled circuit, it is important that the relay is of an appropriate voltage rating configuration for use in a set-up of the controlling circuit and the controlled circuit. If an inappropriate relay were to be used, this may lead to the misoperation of the relay and/or, eventually, to the failure of the circuits in the electrical system.
To enable a compatible plug to couple to its complimentary socket, attempts have been made to ensure that the compatible plug is coupled to the correct socket. Such attempts include visual indications such as labeling (for example, a plug labeled “A” for a socket labeled “A”, a plug labeled “220V” for a socket labeled “220V”, etc.); and color coding (for example, a plug with a red plug housing for a socket with a red socket housing, a plug with a blue plug housing for a socket with a blue socket housing, etc.).
Currently available relays or plug-in relays have indications of voltage rating configurations printed on their housings, or have colored (usually red for AC configurations or green for DC configurations) pushbuttons installed thereon for visual indications on the different types of plug-in relays. However, no corresponding indications of the voltage rating configurations are provided on the relay sockets receiving these relays. A relay socket, unlike a relay or a plug-in relay, typically does not carry any permanent indications of its voltage rating configuration because the relay socket is used for connecting to different set-ups for the controlling circuit and/or the controlled circuit and would therefore be subject to a voltage rating configuration that is dependent on each set-up.
As a result of the absence of any indication on the relay socket on the specific voltage rating configurations, it is difficult for users to easily, quickly and accurately identify the matching relay or plug-in relay for the specific socket. Consequently, a high possibility of relay plug and socket mismatch still exists.
Providing visual indications and colored pushbuttons for labelling the relay plugs to their specific voltage configuration are also not adequately effective in preventing or at substantially reducing the likelihood of a relay socket and plug-in relay mismatch since oversight still occurs frequently.
Therefore, there is a need to provide a socket, a plug, and a plug and socket assembly that overcome or at least ameliorate the disadvantages mentioned above.
There is also a need to provide a relay socket, a relay plug, and a relay plug and relay socket assembly that improve usability.